Quantum dots, also called nanocrystallines, are nano-particles composed of II-VI or III-V elements. The particle size of quantum dots is generally 1 nm to 10 nm. Since electrons and holes are quantum confined, the continuous energy band structure becomes a discrete energy level structure having molecular properties, which may emit fluorescent light when excited. Hence, quantum dots are widely applied in the field of display. For a structure layer in which quantum dots are distributed, i.e., a quantum dot layer, when excited by a light source, quantum dots distributed in the quantum dot layer may emit light of different chromaticity.